Tubing for and method of making bends



` Oct. 17, 1933. J. H. TAYLOR TUBING FOR AND METHOD OF MAKING BENDS Filed Jan. l5, 1931 Patented Oct. 17, 1933 i UNITED STATES PATENT ori-ica TUBING Foa AND METHOD or MAKING BENDS James Hall Taylor, Oak Park, Ill. l Application January 15, 1931. Serial No. 508,819

15 Claims. (Cl. :Z9- 157) This invention relates to the making of pipe of tubing disposed between apair of opposed dies, elbows and other pipe bends, and has to do more illustrating the first step of my method; particularly with a method for producing bends Figure 2 is an end view of the tubing; from suitable lengths of wroughtmetal tubing, Figure 3 vis a view similar to Figure 1, illustrat- I- and with tubing intended for use in the-producing the second step of my method; 5 tion of pipe bends. Figure 4 is an end view of the' tubing after the It is known in the art to produce elbows and inner side thereof has'been pre-shaped as in Figthe like by bending lengths of tubing in dies or ure 3; other means. In bending a straight piece of Figure 5 is a section through the tubing takenl 10 tubing to produce an elbow, the side of the tubsubstantially on line 5 5 of Figure 3;

ing corresponding to 'the shorter or inner side Figure 6 is a sectional view through an elbow of the elbow is, in effect, drawn about a curved produced from the tubing of Figure 3, and forming surface, for instance as disclosed in my through the dies for producing such elbow, parts Patent No. 1,598,893, dated September '1, 19.26. being showninelevation.

This causes thinning of the wall at the inner side Figure 7 is a sectional view taken lengthwise 70 of the elbow, which thinning is objectionable as through the tubing, illustrating an alternative reducing the strength of the elbow at the pormethod of preforming the tubing; v tion thereof which is subjected to greatest stress Figure 8 is a view similar to Figure 3 but illuswhile also interfering with proper welding of the trating a. second alternative method of preform ends of the elbow to pipes or tubes connected ing the tubing;

thereby. I have found that this objectionable Figure 9 is an end view of the tubing used in thinning of the elbow at the inner side thereof the method of Figure 8. can be avoided by properly pre-shaping the inner In Figure 1 I have illustrated a length of tubing side portion of the tubing corresponding to the 'I of wrought metal, this length of tubing havinner side of the elbow, and then imparting the ing its ends cut on planes converging toward the 90 desired nal curvature to the tubing'to produce shorter side of the tubing. This tubing may be the elbow. considered as constituting a blank from which One of the main objects of my invention is to an elbow is to be produced. The longer or upper -provide a method whereby thinning of the inner (as considered in Figure 1) side of the tubing side of the elbow avoided. A further object corresponds to the outer side of the elbow to be 85 is to provide a method in which standard size produced and the shorter side of the tubing cortubing, corresponding in diameter to the diamresponds to the inner side of the elbow. For coneter of the elbow to be produced, may be used in venience in description, therefore, the longer side the production of pipe elbows and bends withof the tubing will be referred to as the outer side out thinning of the wall at the inner side of the and the shorter side as the inner side. 90

4 elbow. A further object is to provide a method In practicing my method, the inner side of the in which the inner side of the .tubing is pre. tubing is heatedinasuitable mannertoafiowing shaped and the ends of such inner side are upheat. that iS, a hea? at Which the metal Will readset or thickened slightly, preliminary to the bendily 110W When SubleCted t0 pressure The area ing of the tubing into its final form to produce over which the tubing is heated, indica/ted at 8, is 95 the elbow, the pre-shaping of the inner side of 0f approxlmately Senu'emptical sha and ex' tends an appreciable distance u rdly, or toil;8h23?rldulgnhfx tlegr ward the outer side of the tubing, from the innerV side of the tubing in the mm1 shaping of the dlllcegwellebmg, igsreg hn; 10o elbow is avoided' It is also an ob'lect f.my 10 therein of slightly greater vertical height or invention to Produce lengths of tubing nnfncu' thickness than the initial thickness. er the wan of larlya'dapted for forming into pipe bends and so the tubing 7, and the dies are moved toward shaped as to avoid objectionable thinning of the each other sa that the end portions of the inner walls at the ends of the inner -side or curve of side of the tubing are disposed inthe recesses 10. 106

the bend produced. Further objects and advan- This is illustrated in Figure 1 Continued movetages 0f my invention will appear from the dement of the dies toward each other subjects the tailed description. 'inner portion of the tubing toendwise pressure In the drawi/ngzexerted simultaneously upon the heated ends or Figure 1 is a sectional view through a length areas 8 with the result that such ends are bent 110 outwardly ofthe tubing, the tubing, as a whole,

central plane thereof remaining unchanged. In

addition to bending the ends 11 of the inner portion of the tubing outwardly, the dies exert an upsettingaction upon-ends 11 so as to increase the thickness of the wall thereof. The outward bending of ends 11 is such that the central portion of the inner side of the tubing, that is, the area between the ends 11, is of arcuateshape and conforms in general to approximately the desired final curvature of the inner side of the tubing.

After the tubing has been preformed at the inner side thereof, in the manner described, it is then'shaped by suitable means to produce the desired elbow. I have illustrated, by way of example, die means suitable for producing an elbow from the tubing of Figure 3. This means is disclosed in ldetail in the co-pending application of Jorge Maroto, for Method and means for forming pipe elbows, Serial No. 496,615, filed November 19, 1930. It is not-necessary to describe in detail the die mechanism, and a brief description thereof will suice. Referring to Figure 6, I provide opposed exterior dies- 13 and 14 having relative movement toward and away from each other. The die 13 is provided with a suitable cavity deiinng a forming surface corresponding in curvature to the desired curvature of the inner side of the elbow. This die, therefore, is termed the inner die. Die 14 is provided with a suitable cavity dening a forming surface corresponding to the curvature of the outer side of the elbow and is, accordingly, termed the outer die. Horn dies 15, having converging and diverging movement toward and away from each other, operate between the dies 13 and 14 insynchronism therewith, the outer sides of dies 15 being curved to conform to the desired curvature of the outer side of the elbow. After the tubing has been pre-formed as in Fig. 3, it is placed in outer die 14 in symmetrical relation thereto, which outer die may be considered as the movable die for.

purposes of description. As die 14 moves toward die 13, the horn dies 15 are projected into the ends of the tubing and serve to progressively.

bend the tubing lengthwise.

horn dies 15, and-the horn dies act to shape the inner side of the tubing about the forming surface of die 13. .The length of tubing is thus shaped to nal curvature to produce the com-- pleted elbow 16. In this final shaping of the tubing, the end portions thereof are compressed radially by the action of the dies so as to be reduced in cross area to the original cross area of the tubing. Since the ends 11 of the inner side of the tubing are bent outwardly of the tubing by the dies 9, the norn dies 15 act to swing these ends 11 outwardly of the tubing about the lines of juncture between the ends 11 and the central area 12 ofthe inner side ofthe tubing, and the inner side of the tubing isshaped accurately about thev forming surface of die- 13 without any appreciable thinning thereof, particularly at the ends, and in the finished elbow the wall at each end of the inner sideof the elbow is at least as thick as,y and in most instances thicker than, the initial thickness of the wall of the tubing before bending thereof. In this manner, thinning of the irmer side of the elbow is avoided, and I render it possible to use standard tubing of the same diameter as the desired diameter of the elbow to be produced. By bending the ends of the inner side of the tubing outwardly, in the preforming thereof, the shaping of the inner side of the tubing about the forming sur-y face of the inner die 13, in the production of the elbow, is facilitated and thinning of the wall of the inner side is prevented, the upsetting or thickening of theends 11 providing an additional safeguard against thinning of the inner side of the elbow, particularly at the endsA thereof. While my method is particularly adapted for the production of elbows, in its broader aspects it is applicable tobends of various types.

It is not essential in all cases, that the end portions of the tubing be moved outwardly thereof as in Figure 3. I find that it is suilicent, in certain cases, if the end portions of the inner side of the tubing be thickened slightly. This result Y can readily be accomplished by stoppingthe 100 movement of the dies 9 toward each other before outward bending of the end portions of the inner side of the tubing occurs. In Figure '7 I have i1- lustrated a p'iece of tubing 17 treated in this manner. The end portions 17*1 have been slightly upset or thickened by the straight line pressure exerted thereon by the dies. thus rendering available additional metal at the inner side of the tubing and in suilicient quantity to compensate for any tendency toward thinning of such inner side in the shaping of the tubing into the elbow. The piece of tubing, preformed in this manner, is then bent to form the elbow in a suitable manner, as by the die means of Figure 6.

InFigures 8 and 9 I have illustrated a further variation of my method. In this form of my method, I provide a piece of tubing 18 of elliptical cross section, the shorter axis ofthe cross sectionof which corresponds approximately to the diameter of the desired elbow. The 120 inner or shorter side of this tubing is subjected to endwise pressure, as in Figure 3, in proper amount to bend the end portions 18* outwardly of the tubing and also cause inward movement of the center portion 18b to such an extent as to 125 reduce the cross sectional area of the center of the tubing to approximately that of the desired elbow. The tubing is then bent to form'the elbow as before. lInstead of using tubing "of elliptical cross section, I may use tubing of cir- 130 cular cross section but of greater diameter than the desired elbow.

` While the recesses of the dies 9 are preferably somewhat thicker than the initial thickness of the wall of the tubing, this is 'not always necessary. 135 It is practicable, in certain cases, to have the die lrecesses such that no appreciable upsetting or thickening occurs at the ends of the inner side of the tubing. With' such dies, upon movement of the dies toward each other, the end portions of the inner side of the tubing are bent outwardly of the tubing, as in Figure 3, 'but are not thickened. This results in stretching of the ends of the tubing, and causes a redistribution of metal in such manner as to render available, at the inner side of the tubing, additional metal to compensate for any tendency toward thinning of. such inner side in the bending of the tubing to form the elbow. It is not essential that the initial thickness of the ends of the inner side of the tubing be mainno y tained, it being sufficient if the displacement and redistribution-of metal is suchas to accomplish the desired result. This preformed tubing is then shaped to the desired nal size and curvature in a `suitable manner, as by the die means of Figure 6.

In the forming of the elbow, the ends of the tubing are reduced in cross area, and the displaced metal flows to the inner side of the elbow, particularly at the ends thereof, and effectively pre- I'vents any'objectionable thinning thereof. j In all of the possible'variations of my method disclosed, metal at the ends of the tubing is dis- -of the tubing is redistributed in the manner and for the purpose above set forth.

What I claim isz- -1. The method of producing pipe elbows and the like,- which consists in providing a straight piece of metal tubing of properlength to form an elbow, then upsetting the metal at the ends of the -side of the tubing corresponding to the inner side of the elbow to be produced and shortening said side of the tubing to render available at the ends of the tubing additional metal for assuring proper thickness of metal at the inner side of the formed elbow, and then bending the tubing to final size and curvature.

clined planes converging toward one side of the tubing, then applying endwise pressure to the shorter side of the tubing to thicken the end portions of said shorter side and move the same outwardly of the tubing, and then bending the tubing to nal size and curvature with the shorter side thereof at the inner side of the bend.

3. The method of producing pipe elbows and the like, which consists in `providing a piece of metal tubing of proper length to form an elbow and with its ends cut on oppositely inclined planes converging toward one side of the tubing, subjecting the end portions of the shorter side ofthe tubing to endwise pressure and thereby moving said end portions outwardly of the tubing while also moving the central portion of the shorter side inwardly of the tubing and shortening said shorter side, and then shaping the tubing to final size and curvature with the shorter side at the inner side of thebend.

4. vThe method of producing pipe elbows and the like, which consists in providing a piece of metal tubing of proper length to form an elbow and with its-ends cut on oppositely inclined planes converging toward one-.side of the tubing, subjecting the end portions ofthe shorter side of the tubing to endwise pressure and thereby upsetting said end portions and moving them outwardly of the tubing while also moving the central portion of the shorter side inwardly of the tubing and shortening said shorter side, and then shaping the tubing to final size and curvature with the shorter side thereof Aat the inner side of the bend.

5. The method of producing elbows' and the like, which consists' in providing a piece of metal thereof tubing of suitable length to form an elbow and of greater cross sectional area than that of the desired elbow, the ends of the tubing being cut on oppositely -inclined planes converging toward one side of the tubing, subjecting the end portions of the shorter side of the tubing to endwise pressure and thereby shortening said shorter side and `bending the central portion thereof inwardly of the tubing, and then bending the tubing to nal size and curvature with the shorter side thereof at the inner side of the bend.

6. The method of producing pipe elbows and the like, which consists in providing a piece of metal tubing of yproper length to form an elbow, then upsetting a portion of each end of the tubing and thereby increasing'the thickness of the wall of the tubing at the ends thereof, and then bending the tubing to final curvature with the upset portions at the inner side of the bend.

7. The method of preforming a length of metal tubing for bending into elbows and the like, which consists in subjecting a selected portion of the tubing to endwise pressure and thereby simultaneously bending the ends of said portion outwardly of the tubing and thickening the same. 8. As a-new article of manufacture, a length of tubing having inwardly converging areas at the ends bent outwardly of the tubing, the ends of the tubing being of greater cross sectional area than the center thereof.

9. As a new article of manufacture, a length of tubing having inwardly converging areas at the ends thereof bentv outwardly of the tubing, the ends of the tubing being of'greater cross sectional area' than the center thereof and the wa.' of each of the outwardly bent areas being of increased thickness relative to the remainder of the wall of the tubing. 1

10. The method of producing pipe bends, which comprises first subjecting the wall at the short side of a piece of tubing with oblique converging ends to endwise pressure between die surfaces spaced to permit upsetting, and then bending said piece of tubing with said short side forming the inner curve of the bend.

11. The method of producing pipe bends, which comprises first subjecting the wall at the short side of a piece of tubing with oblique converging ends to endwise pressure between die surfaces spaced to permit upsetting, thus thickening said wall at said short side, and then bending said piece of tubing with said short side forming the inner curve, thereby restoring said Wall at said short side to normal thickness.

12. The. method of producing pipe bends, which comprises rst upsetting and thereby thickening an inwardly converging area at each end of the wall at the short side of a piece of tubing with oblique converging ends, and then subjecting said piece of tubing to the action of produced, whereby said piece of vtubingv is bent with said short side forming the inner curve.

13. The method of producing pipe bends, which comprises subjecting the wall atthe short side of a piece of tubing with oblique converging ends to endwise pressure between die surfaces spaced to permit upsetting, and bending said piece of -tubing with said short side forming the inner side of .the bend.

14. The method of producing pipe bends, which comprises subjecting to endwise pressure the wall of a piece of 4tubing at the side thereof corresponding to the inner curve of the bend to be produced and thereby bulging said wail inwardly of the tubing, and bending the` pieceA of tubing with said bulged side thereof forming the inner curve of the bend. A

15. 'I'he method of producing pipe bends, which comprises subjecting the'wall at the short side oi.' a piece of tubing with oblique converging 

